The beauty of it comes when you're working in a team of say 5 other front end devs of varying skill levels. There tends to be a large amount of duplication & overlap, people have different ways of doing things and achieving certain looks. If everyone agrees to use tailwind, you stop people from writing custom code which is ultimately a good thing because custom code requires custom comments and custom documentation etc which let's face it - nobody does or wants to do and even if they do, it's not maintained to the sort of standard tailwind docs are.